KEYTABLES(5)
NAME
keytables - keyboard table descriptions for loadkeys and
dumpkeys
DESCRIPTION
These files are used by loadkeys(1) to modify the transla-
tion tables used by the keyboard driver and generated by
dumpkeys(1) from those translation tables.
The format of these files is vaguely similar to the one
accepted by xmodmap(1). The file consists of charset or
key or string definition lines interspersed with comments.
Comments are introduced with ! or # characters and con-
tinue to the end of the line. Anything following one of
these characters on that line is ignored. Note that com-
ments need not begin from column one as with xmodmap(1).
The syntax of keytable files is line oriented; a complete
definition must fit on a single logical line. Logical
lines can, however, be split into multiple physical lines
by ending each subline with the backslash character (\).
A character set definition line is of the form:
charset "iso-8859-x"
It defines how following keysyms are to be interpreted.
Each complete key definition line is of the form:
keycode keynumber = keysym keysym keysym...
keynumber is the internal identification number of the
key, roughly equivalent to the scan code of it. keynumber
can be given in decimal, octal or hexadecimal notation.
Octal is denoted by a leading zero and hexadecimal by the
prefix 0x.
Each of the keysyms represent keyboard actions, of which
up to 256 can be bound to a single key. The actions avail-
able include outputting Latin1 character codes or charac-
ter sequences, switching consoles or keymaps, booting the
machine etc. (The complete list can be obtained from dump-
keys(1) by saying dumpkeys -l .)
Each keysym may be prefixed by a '+' (plus sign), in wich
case this keysym is treated as a "letter" and therefore
affected by the "CapsLock" the same way as by "Shift" (to
be correct, the CapsLock inverts the Shift state). The
ASCII letters ('a'-'z' and 'A'-'Z') are made CapsLock'able
by default. If Shift+CapsLock should not produce a lower
case symbol, put lines like
keycode 30 = +a A
in the map file.
Which of the actions bound to a given key is taken when it
is pressed depends on what modifiers are in effect at that
moment. The keyboard driver supports 8 modifiers. These
modifiers are labeled (completely arbitrarily) Shift,
AltGr, Control, Alt, ShiftL, ShiftR, CtrlL and CtrlR.
Each of these modifiers has an associated weight of power
of two according to the following table:
modifier weight
Shift 1
AltGr 2
Control 4
Alt 8
ShiftL 16
ShiftR 32
CtrlL 64
CtrlR 128
The effective action of a key is found out by adding up
the weights of all the modifiers in effect. By default, no
modifiers are in effect, so action number zero, i.e. the
one in the first column in a key definition line, is taken
when the key is pressed or released. When e.g. Shift and
Alt modifiers are in effect, action number nine (from the
10th column) is the effective one.
Changing the state of what modifiers are in effect can be
achieved by binding appropriate key actions to desired
keys. For example, binding the symbol Shift to a key sets
the Shift modifier in effect when that key is pressed and
cancels the effect of that modifier when the key is
released. Binding AltGr_Lock to a key sets AltGr in effect
when the key is pressed and cancels the effect when the
key is pressed again. (By default Shift, AltGr, Control
and Alt are bound to the keys that bear a similar label;
AltGr may denote the right Alt key.)
Note that you should be very careful when binding the mod-
ifier keys, otherwise you can end up with an unusable key-
board mapping. If you for example define a key to have
Control in its first column and leave the rest of the
columns to be VoidSymbols, you're in trouble. This is
because pressing the key puts Control modifier in effect
and the following actions are looked up from the fifth
column (see the table above). So, when you release the
key, the action from the fifth column is taken. It has
VoidSymbol in it, so nothing happens. This means that the
Control modifier is still in effect, although you have
released the key. Re-pressing and releasing the key has
no effect. To avoid this, you should always define all the
columns to have the same modifier symbol. There is a handy
short-hand notation for this, see below.
keysyms can be given in decimal, octal, hexadecimal or
symbolic notation. The numeric notations use the same
format as with keynumber. The symbolic notation resembles
that used by xmodmap(1). Notable differences are the num-
ber symbols. The numeric symbols '0', ..., '9' of
xmodmap(1) are replaced with the corresponding words
'zero', 'one', ... 'nine' to avoid confusion with the
numeric notation.
It should be noted that using numeric notation for the
keysyms is highly unportable as the key action numbers may
vary from one kernel version to another and the use of
numeric notations is thus strongly discouraged. They are
intended to be used only when you know there is a sup-
ported keyboard action in your kernel for which your cur-
rent version of loadkeys(1) has no symbolic name.
There is a number of short-hand notations to add readabil-
ity and reduce typing work and the probability of typing-
errors.
First of all, you can give a map specification line, of
the form
keymaps 0-2,4-5,8,12
to indicate that the lines of the keymap will not specify
all 256 columns, but only the indicated ones. (In the
example: only the plain, Shift, AltGr, Control, Con-
trol+Shift, Alt and Control+Alt maps, that is, 7 columns
instead of 256.) When no such line is given, the keymaps
0-M will be defined, where M+1 is the maximum number of
entries found in any definition line.
Next, you can leave off any trailing VoidSymbol entries
from a key definition line. VoidSymbol denotes a keyboard
action which produces no output and has no other effects
either. For example, to define key number 30 to output 'a'
unshifted, 'A' when pressed with Shift and do nothing when
pressed with AltGr or other modifiers, you can write
keycode 30 = a A
instead of the more verbose
keycode 30 = a A VoidSymbol VoidSymbol \
VoidSymbol VoidSymbol VoidSymbol ...
For added convenience, you can usually get off with still
more terse definitions. If you enter a key definition line
with only and exactly one action code after the equals
sign, it has a special meaning. If the code (numeric or
symbolic) is not an ASCII letter, it means the code is
implicitly replicated through all columns being defined.
If, on the other hand, the action code is an ASCII charac-
ter in the range 'a', ..., 'z' or 'A', ..., 'Z' in the
ASCII collating sequence, the following definitions are
made for the different modifier combinations, provided
these are actually being defined. (The table lists the
two possible cases: either the single action code is a
lower case letter, denoted by 'x' or an upper case letter,
denoted by 'Y'.)
modifier symbol
none x Y
Shift X y
AltGr x Y
Shift+AltGr X y
Control Control_x Control_y
Shift+Control Control_x Control_y
AltGr+Control Control_x Control_y
Shift+AltGr+Control Control_x Control_y
Alt Meta_x Meta_Y
Shift+Alt Meta_X Meta_y
AltGr+Alt Meta_x Meta_Y
Shift+AltGr+Alt Meta_X Meta_y
Control+Alt Meta_Control_x Meta_Control_y
Shift+Control+Alt Meta_Control_x Meta_Control_y
AltGr+Control+Alt Meta_Control_x Meta_Control_y
Shift+AltGr+Control+Alt Meta_Control_x Meta_Control_y
All the previous forms of key definition lines always
define all the M+1 possible modifier combinations being
defined, whether the line actually contains that many
action codes or not. There is, however, a variation of
the definition syntax for defining only single actions to
a particular modifier combination of a key. This is espe-
cially useful, if you load a keytable which doesn't match
your needs in only some modifier combinations, like
AltGr+function keys. You can then make a small local file
redefining only those modifier combinations and loading it
after the main file. The syntax of this form is:
{ plain | <modifier sequence> } keycode keynumber = keysym
, e.g.,
plain keycode 14 = BackSpace
control alt keycode 83 = Boot
alt keycode 105 = Decr_Console
alt keycode 106 = Incr_Console
Using "plain" will define only the base entry of a key
(i.e. the one with no modifiers in effect) without affect-
ing the bindings of other modifier combinations of that
key.
In addition to comments and key definition lines, the
keytable files can contain string definitions. These are
used to define what each function key action code sends.
The syntax of string definitions is:
string keysym = "text"
text can contain literal characters, octal character codes
in the format of backslash followed by up to three octal
digits, and the three escape sequences \n, \\, and \", for
newline, backslash and quote, respectively.
To find out what keysyms there are available for use in
keytables files, use the command
dumpkeys --long-info
Unfortunately, there is currently no description of what
each symbol does. It has to be guessed from the name or
figured out from the kernel sources.
EXAMPLES
(Be careful to use a keymaps line, like the first line of
`dumpkeys`, or "keymaps 0-15" or so.)
The following entry exchanges the left Control key and the
Caps Lock key on the keyboard:
keycode 58 = Control
keycode 29 = Caps_Lock
Key number 58 is normally the Caps Lock key, and key num-
ber 29 is normally the Control key.
The following entry sets the Shift and Caps Lock keys to
behave more nicely, like in older typewriters. That is,
pressing Caps Lock key once or more sets the keyboard in
CapsLock state and pressing either of the Shift keys
releases it.
keycode 42 = Uncaps_Shift
keycode 54 = Uncaps_Shift
keycode 58 = Caps_On
The following entry sets the layout of the edit pad in the
enhanced keyboard to be more like that in the VT200 series
terminals:
keycode 102 = Insert
keycode 104 = Remove
keycode 107 = Prior
shift keycode 107 = Scroll_Backward
keycode 110 = Find
keycode 111 = Select
control alt keycode 111 = Boot
control altgr keycode 111 = Boot
Here's an example to bind the string "du\ndf\n" to the key
AltGr-D. We use the "spare" action code F100 not normally
bound to any key.
altgr keycode 32 = F100
string F100 = "du\ndf\n"
SEE ALSO
loadkeys(1) dumpkeys(1) showkey(1) xmodmap(1)